![Keck Observatory](https://www.astronomy.com/wp-content/uploads/sites/2/2023/02/asy-20010315-00712-500.jpg)
The two large Keck telscopes can combine their light-gathering power through interferometry to probe the universe.
NASA/JPL
Digital interferometry is possible with low-frequency radio wavelengths, but not with light in the high-frequency optical portion of the spectrum.